Page 76 - Koi Net - On-Line Koi Magazine - Issue 92
P. 76
Algae doesn’t need much explanation. Algae can use I don’t even need to find evidence for this first standard
Ammonia and nitrate to grow and thus reduce the level part as the evidence is in previous articles. It is well-
of these substances in the water. The floating algae are known as the effect that arises at the start of a new
usually prevented/killed with UV lamps and the blanket pond or growth tank. First, an Ammonia peak is
algae we extract from our ponds, or we create shade measured, then a Nitrite peak, and then a Nitrate peak.
making it a lot harder for the algae to grow. If you have
more algae as autotrophs and your Ammonia level in the
pond (with some sun) goes up, then you get algae growth. Start-up Curve for a Biological Filter
Thus remain the autotrophic and heterotrophic bacteria
TAN NO ² NO ³
but actually also two other routes which were not
Biofiltration
discussed in this article because they did not apply here. Nitrification
There are also routes without oxygen namely Nitrification
15
Denitrification and Anammox. In the next article these are
described in more detail.
First the standard Autotroph bacteria. The basis of 10
Nitrogen Flow (no ‘Cycle’) like it is always learned and Concentration (ppm)
taught in the Koi world. As is known, nitrification and the Removal Rate (g/m 3 per day) 5
degradation of nitrite by Nitrosomonas and Nitrobacter
among others convert Ammonia to nitrate via nitrite (in the
following diagrams). Degradation to Nitrite by bacteria 0
from Nitrosomonas, Nitrosococcus, Nitrosolobus, 0 7 14 21 28 35 42
Time (Days)
Nitrospira and Nitrosovibrio, breakdown of Nitrite by
Nitrobacter, Nitrococcus, Nitrospira and Nitrospina. These Recirculating Aquaculture Systems Short Course.
processes give the bacteria energy to continue to do
everything in the bacterial cell. The Ammonia peak comes after 14 days, followed by
nitrite on 28 days and last, the nitrate really rises from
A schematic overview of most processes 21 days onwards higher as the nitrite peak decreases.
looks like this:
Recently, well, at the end of 2015, a new addition to this
The Nitrogen Cycle
became known. In Nature, December 2015 it is
described that there are Nitrospira subspecies that
breakdown Ammonia and nitrite to nitrate at once. And
they do not prove rare but were found in many places in
N org NH 4 + NO 2 - NO - nature. They were called Comammox, complete
³
Ammonia oxidiser. Interestingly enough, these bacteria
NO do not excrete any nitrite, this step is skipped. This
subgroup of Nitrospira was then found in different filters
N 2 O and wastewater treatment systems and therefore
N 2
certainly proved not rare. According to the authors, it
Ammonia Oxidation to Nitrite (Nitritation) Complete Ammonia Oxidation to seems more that there is a kind of balance in those
Nitrate (Comammox)
Nitrite Oxidation to Nitrate (Nitratation) biofilms between the different Nitrospira and other
Anammox Process Dissimilatory Nitrate Reduction
to Ammonium (DNRA)
Denitrification Ammonia users, but it was always present. In one of the
Nitrogen Fixation
measurement results, 43-71% of the Nitrospira found
Intermediates for Nitritation, Comammox and Anammox are not depicted.
present were Comammox.
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